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A new Raidboat and Cruising Dinghy Design for the Home Builder

Hello!

In this thread I will start to design a new Raidboat (or Fast Cruising Dinghy) for home- and professional builders alike. It will be on the simple, fast and cheap side of construction with as few parts to be built as possible. But it will be but not a „simple as can be“ design to allow all the features that make sailing and cruising live safe and comfortable.

On the sailing side it will be a fast and lively boat with a good overall performance and balance, able to sail many miles a day. Easy Daysailing with your partner and one kid is also a design target as well as racing on club races.
For me Lightweight construction and -displacement is the key to reach the targets and also allows easy trailering and -handling on the beach.

Safety is another important topic in this design. Recovery from capsize, self bailing cockpit and getting back aboard ... I will turn attention to these topics

Concept Catalogue

GeneralThis boat is meant to be a singlehander for cruising and cruising raids and can take up to two crew and a kid for daysailing. When sailing in club races it shall not automatically earn the red lantern.

Length over all will be two sheets of plywood long, meaning a little under 16feet. So it will be a long and light boat for a single hander and therefore a fast one due to the long waterline.

Safety: A raised floor for a self bailing cockpit after recovering from capsize, no bailing out water when sailing in strong winds and waves, no need for Elvström bailers, no wet sleeping bag when sleeping in the boat.

No side tanks (a la 470 or 420) to allow the boat to sink in a little when capsized. This helps to reach the daggerboard from swimming to re-right the boat. It also makes the boat roll back more slowly, so that you can climb back into the boat in one rush as the boat becomes upright. The boat will stay at 90° heel when the mast is nearly parallel to the waterline and will have no tendency to become 180°.A safety ladder for getting aboard after capsize as well for taking a bath when anchoring.

A sea anchor keeps the boat with the bow into the wind while reefing or capsizing.

Water ballast will calm the boat down when sailing in strong winds and inceases the stability. It also helps to re-right the boat. Off course the ballast tank is empty in light winds and regattas.

Performance and Balance

Sharpie hull with flaring sides. Sharpie hulls offer good performance when designed with care. In a modern design like this one they have a slim waterline for low resistance and good planing abilities. The center of flotation is slightly aft of the middle to allow an effective trim from the aft sitting skipper. The flaring hullsides increase the sailing stability when sailed heeled and dampen the tendence to capsize. They also make hiking out more effective.

Lightweight construction. The lighter the boat, the faster it is … so simple. Even if this design is a cruising dinghy and has to carry a lot of stuff beside the crew, for me performance is important. Take out all the cruising stuff and have some fun racing on club regattas. Overall boatwheight ready to sail but without cruising gear should be well under 90kg.

Effective sail plan. Cruising Dinghys need a sailplan with a low center of effort and the ability to reef easily to make sailing safe. Singlehanders are suited best if they have only one sail to handle. I have chosen to use the balanced lug sail with a large sail area as the standard rig for my design. It can be trimmed very good to balance the boat upwind and is very neutral and effective when the wind is coming from the side or behind. Mast will be free standing without the need for shrouds.

I know that a lot of sailors prefer the yawl rig for cruising so this rig will be an option in the plans. On the downside of this rig I see the building effort of 3 to 4 more spars and the cost of two sails instead of one. And the loss of efficency of the departed sail area, the increased wind resistance and the wheight of the aditional spars.

The rig of the OK-Dinghy or other singlehanded dinghys is another option. Even the sails from a windsurfer can be rigged, but this would be a experiment on your own risk. Windsurfer sails cannot be reefed.

Comfort

Side decks for comfortable sitting and hiking out over a long time.

Sleeping inside the boat is possible on the uncluttered raised floor and unter a custom deck tent. This is important in my home country as „wild“ camping is not allowed in Germany.

Dry stores are under the raised floor in the forward part of the boat, reachable through watertight hatches in the floor. Here are fixed places for the anchor, water supply and other heavy gear that will double act as ballast. A step upwards in the raised floor brings here a height of more than 30cm (1').

High sides for dry sailing in the sitting area midships

Construction

Construction will be sitch and glue, the fastest and most effective construction method for plywood. Every part you build will also be in boat later. No need to waste time and money on a buiding jig or temporary moulds. Okume marine grade plywood with 6mm, 5ply will be used for all parts of the hull. 4 frames/bulkheads plus stem and stern will form the transvers members. Only one stringer will be in the hull sides, mainly to be the base for the raised floor.

The Sharpie Hull is the fastest and simplest hull to build and with it's three panel layout also the cheapest one to put together. There is nearly no waste in the panels

The round Mast will be made from wood in the birdsmouth technique and rectangular sections for boom and yard.

As far as I can see it now you will need 7 sheets of plywood and 12 – 15kg of multi purpose Epoxy for glueing, sheeting and laminating glasfibres. Opposite to 5 sheets of ply for a „simple as can be boat“ of the same 16 feet lenght. In my oppinion it is worth the extra effort.

That's it for now!

I'am open for comments and incitements. If you have other topics and ideas to be minded let me know and I will try to incorporate them into the design.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Hello Frank,
yes, Michael Storer designed a raidboat a few years ago and two prototypes (as far I know) were built. They had serious problems, so Storer decided not to offer plans for the boat. His design was more a slim sailing canoe and built super light to be carried on top of a car. Afterwards he made no futher attempt to devellop a dinghy for cruising and raids.

I focus on sailing stability and safety, in my opinion very important features in a cruising dinghy.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Michel, I meant the Goat Island Skiff. Joost Engelen used her with his wife in a 'Dorestad Raid, and earlier in the Great Glenn Raid. Don't know if she planed, probably not with the 2 of them aboard. Late rhe built a Storer canoe named Viola, and I think she is pretty succesful.
Will you come to the Dutch Woodenboatshow in Den Helder next weekend? There will be raid people, and I would like to meet you.
Frank

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Frank,
of course I know the GIS, I have built one for a customer and sailed it too. To be honest ... on that GIS I have made my first experiences with a balanced lug sail. The Hull of the GIS is a very good example for a modern light displacement hull and the performance possible with the sharpie form. And of course she planed with two crew, not with all that cruising stuff on a raid, but while daysailing and a good wind ... sure she did!
But the GIS is not designed as a cruising boat, it is a daysailer. It lacks all the details that makes sailing safeer and more comfortable, mentioned above in my first post.

Next weekend I will meet my girlfriend in Wilhelmshaven. We live separatly and meet every second weekend. I will have to check first if we make a jaunt to Den Helder. Do you already know on which day(s) you will be at the festival?

Even if I cannot visit the festival, we can chat about designs privatly and meet later.

Have fun! Michel

Last edited by luckystrike118; 06-29-2019 at 07:35 PM.
Reason: correction

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Originally Posted by luckystrike118

Hello Frank,
yes, Michael Storer designed a raidboat a few years ago and two prototypes (as far I know) were built. They had serious problems, so Storer decided not to offer plans for the boat. His design was more a slim sailing canoe and built super light to be carried on top of a car. Afterwards he made no futher attempt to devellop a dinghy for cruising and raids.

I focus on sailing stability and safety, in my opinion very important features in a cruising dinghy.

Have Fun! Michel

One of the boats (the US one) was actually sailed by Michael Storer and I understand that the boat handled well and sailed fast. Two links to videos (in the second video Michael Storer is at the helm):

Michael’s comments were: “The boat was not a complete success. It was too hard to get back aboard after a capsize, but it is as nice to sail as the Goat Island Skiff, goes smoothly and quickly upwind and planes away downwind.”

Due to the double floor, the sides became very high making it difficult to re-board the boat after a capsize. But perhaps some alterations (lower the sides and leave out the double floor) would have fixed this. That would have meant a big job (complete re-design!) and the project was shelved for not working consistently enough.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

I can confirm that the Goat Island Skiff readily planes, also with two persons aboard (and with light camping kit), when the conditions are right. I agree that there is limited space for carrying gear and that sleeping on board is very difficult (it has been done, but I would never consider doing this myself). Hence your proposition for a raised deck forward and the double floor, I guess, to take care of these 2 issues.

To my eyes, the hull shown above shows much resemblance to the GIS save for the reverse bow, reverse transom and the reverse sheer. Obviously there is only so much one can do for a performance boat having a sharpie hull shape.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Hello Joost,

you wrote: your proposition for a raised deck ...

My design will not have a raised deck, my fault. I have chosen the wrong term due to a little confusion while writing the very long first post. The correct term ist raised floor, I have corrected this in the post.

you wrote: Obviously there is only so much one can do for a performance boat having a sharpie hull shape.

A designer once wrote: "Sharpie hulls are easy to build, but difficult to design"

This is true. I'am studying sharpie hulls for more than 10years now, for monohulls and multihulls alike. And you are right! If you want to transfer a modern, performance (planing) orientaded hull shape into a sharpie hull you are very limited in the shape of the all important bottom panel. You want to have a broad stern for planing, but the boat must behave like a sharpie in displacement mode (upwinds). That means the forefoot must be out of the water, otherwise you have massive resitance from turbulence around the chine forward. And there are half a dozen other design aspects you have to take care of and that must be done right.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Originally Posted by Joost Engelen

One of the boats (the US one) was actually sailed by Michael Storer and I understand that the boat handled well and sailed fast. Two links to videos (in the second video Michael Storer is at the helm):

Michael’s comments were: “The boat was not a complete success. It was too hard to get back aboard after a capsize, but it is as nice to sail as the Goat Island Skiff, goes smoothly and quickly upwind and planes away downwind.”

Due to the double floor, the sides became very high making it difficult to re-board the boat after a capsize. But perhaps some alterations (lower the sides and leave out the double floor) would have fixed this. That would have meant a big job (complete re-design!) and the project was shelved for not working consistently enough.

I thought the problem was that he made the sides high enough to row comfortably without raised oarlocks. If making it a more pure sailing design, lowering the sides alone should alleviate the problem.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

There has been a Windmill design modification that meets most of the criteria that the OP posted. Michael Jones in St. Petersburg Florida who apprenticed years ago with Clark Mills. Boat is called MALU. http://www.jonesboatworks.com/malu/. A bit bigger and with side tanks as proven to work with Windmills, where the double bottom gave problems self rescueing.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

I thought the problem was that he made the sides high enough to row comfortably without raised oarlocks. If making it a more pure sailing design, lowering the sides alone should alleviate the problem.

Correct. But the raised double floor meant that the hull sides had to be made higher than normal as to maintain a normal rowing position. Leave out the double floor and the height of the sides can go down quite a bit.

Indeed if you would leave out rowing, the height of the hull becomes less of a consideration. But than again the Raid41 was conceived as a raid boat and rowing is normally a vital requirement in the sense of having solid secondary propulsion. Further a very wet boat does not make for a good Raid boat (not very comfortable on long sails).

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Malu is not relevant to this thread, it is designed as a daysailer, not a raidboat

*in this post I will use the term "raidboat", meaning raidboat and cruising dinghy alike, I think its the same breed.*

I agree that high sides are better for dry sailing and this is a important feature in a raidboat.

I think we are closing to main problems of raidboatboat design... (apart from secondary propulsion, important but not so impotant as...)
1. prevent capsize
2. recovering from capsize
3. self resuing

In my opinion and with my experiences in sailing dinghys...

1.1. slim boats like the raid 41 (well under 4' wide and with rectangular sections) capsize more easely and faster. A wider boat gives you more time to ease the mainsheet and prevent capsize. You also have more leverarm when hiking out, making hiking more effective.

2. 1. side flotation tanks let the capsized boat float high and make it more prone to capsize fully to 180° ... opposit to floating stable at ~90° when the hull partly sinks in.

2.2 The absence of side flotation tanks let the boat sink into the water to a certain point and the amount of water in the cockpit slows the motion when the boat is re-righted. This gives you more time to re-enter the cockpit immediatly when the boat becomes upright again.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Just because: Goat Island Skiff planing with two aboard. I could get mine planing with two aboard also if conditions were right, as Joost attests to. Not hijacking thread, this is interesting, but the video is a fun intermission in the convo. Good luck to you Luckstrike!

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Sorry that you found MALU irrelevant. I believe the owner has done a bit of camp cruising in same; the main reason cited is that the Windmill is often ignored in the discussions of sharpie types and they did some interesting work with small side tanks to make the boat self rescueing. Attention needs to be paid to the rig and weight. On my own boat we borrowed lots from International Canoes, creating a high aspect ratio full batten main with spars in carbon and the lug yard in a sleeve, creating a very efficient rig. We kept the weight down by giving it an asymmetric hull, making it a planing double ender like canoe, saving the weight of a transom and creating the adding benefit of a pleasant rowing craft. We did not do a double bottom to save weight and used bags for floatation. A dagger board which needs to be managed adds to the performance and helps the space issue. My boat has wide "rub" rails for comfort hiking and is one of the few raid boats with a toe strap. The topsides have lots of flare. Principle borrowed from the Merlin Rocket.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Originally Posted by luckystrike118

Hello Joost,

you wrote: your proposition for a raised deck ...

My design will not have a raised deck, my fault. I have chosen the wrong term due to a little confusion while writing the very long first post. The correct term ist raised floor, I have corrected this in the post.

you wrote: Obviously there is only so much one can do for a performance boat having a sharpie hull shape.

A designer once wrote: "Sharpie hulls are easy to build, but difficult to design"

This is true. I'am studying sharpie hulls for more than 10years now, for monohulls and multihulls alike. And you are right! If you want to transfer a modern, performance (planing) orientaded hull shape into a sharpie hull you are very limited in the shape of the all important bottom panel. You want to have a broad stern for planing, but the boat must behave like a sharpie in displacement mode (upwinds). That means the forefoot must be out of the water, otherwise you have massive resitance from turbulence around the chine forward. And there are half a dozen other design aspects you have to take care of and that must be done right.

Regards, Michel

UK Cherubs, Australian Skates and seahugging narrow International Moths didn't have much problem with a sharpie-type hull and immersed stem.

The dinghy designers I've been lucky enough to talk to (Bieker, Paterson, Bethwaites etc) often note that modern high performance dinghies often don't have very wide sterns, since the stern doesn't develop planing lift and having a narrower stern reduces wetted surface and allows it to be "sunk" in strong winds, therefore causing the bow to pitch high and stop nosediving. This was particularly noted, for example, when Bieker came into Int 14s and outmoded the wedge-shaped low-chine Australian designs with his U-sectioned narrower waterline boats that went faster and handled better.

I'm very interested in re-boarding ideas, since any boat I've ever sailed would capsize immediately (well, if the winds were strong enough to cause a normal capsize) if you went to the stern to try to get back on board. A couple of times I've ended up helping crew over the stern and really disliked it, since their body caused sufficient drag and shift of CLR to cause the boat to bear away and gain speed, therefore adding to the drag on the crew. I'm not sure if this is a cultural thing, a boat-type issue, or what.

The dinghy designers I've been lucky enough to talk to (Bieker, Paterson, Bethwaites etc) often note that modern high performance dinghies often don't have very wide sterns, since the stern doesn't develop planing lift and having a narrower stern reduces wetted surface and allows it to be "sunk" in strong winds, therefore causing the bow to pitch high and stop nosediving. This was particularly noted, for example, when Bieker came into Int 14s and outmoded the wedge-shaped low-chine Australian designs with his U-sectioned narrower waterline boats that went faster and handled better.

I'm very interested in re-boarding ideas, since any boat I've ever sailed would capsize immediately (well, if the winds were strong enough to cause a normal capsize) if you went to the stern to try to get back on board. A couple of times I've ended up helping crew over the stern and really disliked it, since their body caused sufficient drag and shift of CLR to cause the boat to bear away and gain speed, therefore adding to the drag on the crew. I'm not sure if this is a cultural thing, a boat-type issue, or what.

For some time now I've been teaching that reboarding should be midships, for that very reason. But the boat has to be set up for it, with enough bouyancy there to allow the crew to come in over the side, but not so much that the boat will be impossible to right if "turtled". One way of helping that issue is to have high up bouyancy in the ends, sufficient to float her with the gunwales clear of the water amidships.

Planing hulls? I like wide sterns, but do have more rocker in the after bottom than is usual. That does limit the ultimate speed but tends to get them up on the plane earlier. Its a "horses for courses" thing, and when drawing a cruising dinghy I'm generally aiming for a top end speed length ratio of around 2.25 Much higher than that and the shape starts to change again.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

In the UK "Wild Camping" is camping with a tent (or Tarp 'n' Hammock) outside a recognised campsite - i.e. on any avialable patch of ground.

Common in the thinly populated areas such as northern Scotland and some parts of Wales.

See also "Bothy"

If preventing compete invertion is the object - then a couple of tricks from the catamaran people may be of use:
1 - Foam in the top quarter of the sail - between two layers of lighter sailcloth - Unicorns are doing this.
2 - other raised flotation - a sealed yard on a gunter or lug rig might well work.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

I'm very interested in following this. We just had the inaugural Salish 100 in my back yard and I'm seriously tempted to build a Navigator for next year's. My 12' CLC Passagemaker wouldn't have been a good choice, although it has a payload of 650 pounds. I think it would've been too slow due to waterline and I would've needed to hang a Honda 2.3hp off the back due to tidal currents and light winds.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Originally Posted by wizbang 13

What is "wild" camping ?

Hi,

"wild camping" means camping in a tent outside from specified camping grounds. It is vorbidden in Germany as well as making an open fire. Our forests are burning in summer since a few years due to the climate change, so the latter seems to be right.

But anchoring outside of habours is still allowed and if you can sleep aboard this is a big advantage for a cruising dinghy.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Originally Posted by Plyboy

I'm just looking at the Bolger June Bug and thinking, "Heyyy, what if you scaled this up 10-15% for a beam more friendly to 2 sleepers...."

Hello Plyboy,

I did a quick research for the June Bug, but could not find the length of it. But the Junebug design is a minimum of 40 years old now and a lot of things happened since than, not to mention that it lacks a lot of features mentioned in post No.1.

Anyway, I have some thoughts about a "two sleeper" and a second design to my concept would call for a 18' length (or two and a half sheets of plywood long) to have enough provision für payload and space.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Chris, you are refering to Cherups, Int 14 and "Low Rider" Moths. These are pure racing skiffs and are a total other kind of boat being discussed here.

You are right, racing skiffs will capsize immediatly when nobody is inside the cockpit to balance the boat. Cruising dinghys are much more stable in this situation.

Racing skiffs carry high efficient rigs where the mainsail is providing driving power as soon as the boat bears away and the mainsail is blocked by the shrouds.
A balanced lug with it's free standing mast can swing out towards the bow if the mainsheet is long enough.

John,
I think the best way to get back into the boat is in one rush with the re-righting of the boat. But in real life it will also happen that you are swimming beside. If the boat has more than 20cm freeboard flooded it will be difficult to kick down the sides and climb in without having several 100litres in the cockpit that have to be bailed out before you can start sailing again.

I clearly prefere a self bailing boat with a double bottom and a re-entry over the (broad) stern, having a boarding ladder made from aluminium or steel ready to be pulled out of the cockpit. The freeboard amidships could then also be quite high to have a relativly dry-sailing boat.

For both ways of recovery it would be farvorable to have a sea anchor at the bow to keep the bow into the wind.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Originally Posted by CaptainSkully

I'm very interested in following this. We just had the inaugural Salish 100 in my back yard and I'm seriously tempted to build a Navigator for next year's. My 12' CLC Passagemaker wouldn't have been a good choice, although it has a payload of 650 pounds. I think it would've been too slow due to waterline and I would've needed to hang a Honda 2.3hp off the back due to tidal currents and light winds.

I think the navigator is a wonderful boat, very stylish with it's strong sheer and the classic look. And it has a good reputation as a cruising dinghy. But if you have a wife and kids, and have to work for your living, I think it's impossible to construct a 8 panel hull with all the stylish details within 6 month part time building.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

I'm very interested in following this. ... and I'm seriously tempted to build a Navigator for next year's. I would've needed to hang a Honda 2.3hp off the back due to tidal currents and light winds.

Hello Captain Scully,
I think the navigator is a wonderful boat, very stylish with it's strong sheer and the classic look. And it has a good reputation as a cruising dinghy. But if you have a wife, kids, and have to work for your living, I think it's impossible to construct a 8 panel hull with all the stylish details within 6 month part time building.

A small outboard motor should not be a problem for any cruising dinghy. Some people are lucky with oars, but some are living in areas with tidal currents (In my home waters are places where Iam faced with up to 4knots of t.c.) and simply need an outboard.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Originally Posted by P.I. Stazzer-Newt

If preventing compete invertion is the object - then a couple of tricks from the catamaran people may be of use:
1 - Foam in the top quarter of the sail - between two layers of lighter sailcloth - Unicorns are doing this.
2 - other raised flotation - a sealed yard on a gunter or lug rig might well work.

Hello P.I: Stazzer

Good points too keep in mind. I like the sealed yard. One could give the yard more volume and a aerodynamic shape to reduce turbolence.

The Foamtop is also interesting, but complication will rise the sailmakers bill. I just ordered a lugsail where I eliminated the battens to save 100€.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Chris, you are refering to Cherups, Int 14 and "Low Rider" Moths. These are pure racing skiffs and are a total other kind of boat being discussed here.

You are right, racing skiffs will capsize immediatly when nobody is inside the cockpit to balance the boat. Cruising dinghys are much more stable in this situation.

Racing skiffs carry high efficient rigs where the mainsail is providing driving power as soon as the boat bears away and the mainsail is blocked by the shrouds.
A balanced lug with it's free standing mast can swing out towards the bow if the mainsheet is long enough.

Yes, but the point is that the Paterson-style Cherubs, the Moths and other "sharpie type" high performance boats have immersed stems and still perform well, therefore it seems that there is not actually massive turbulence around the bows of sharpie types. The same applies to Signets and Vauriens, which are slower designs aimed more at beginners, but also have flat-bottomed sharpie-type bow sections and immersed stems and still seem to perform well.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Hi, I'am back from a few day's vacation.

Hello Chris,

I cannot verify if a immersed stem has less or equal resistence compared to a stem which is above the waterline while sailing.
I can just rely on my own experience from three succesful designs and from the general opinion (Storer, Parker, Beckwith) about boat design that a free stem is best for a sailing sharpie.

It may be that a high performance sharpie takes advantage (earlier and faster planing) from the flatter rockerline that goes together with the immersed stem.

But in a cruising dinghy, which will be heavier, I prefer the stem above the waterline. I think this is better for sailing in displacement mode and is better controlable in planing conditions.

Re: A new Raidboat and Cruising Dinghy Design for the Home Builder

Originally Posted by Ben Fuller

There has been a Windmill design modification that meets most of the criteria that the OP posted. Michael Jones in St. Petersburg Florida who apprenticed years ago with Clark Mills. Boat is called MALU. http://www.jonesboatworks.com/malu/. A bit bigger and with side tanks as proven to work with Windmills, where the double bottom gave problems self rescueing.

That's a nice looking vessel.... A buddy has a Windmill. My most vivid memory of that boat is driving it, bow under, in a pretty good breeze on a lake in Oregon. Something a bit bigger, with some more volume in the bow would be very nice.